Social media has been used in massive open online courses (MOOCS) from the beginning of the MOOC movement. Social media platforms such as Facebook, Twitter, and Google Hangouts have provided collaborative and engaging spaces for MOOC students to work together on projects and activities, and for instructors to guide students. Instructional designers partnering with MOOC instructors or MOOC instructors designing and developing MOOCs select the social media platforms used in the MOOC, but it is not currently known how instructors or instructional designers select which social media platforms to use. This study was necessary to understand how MOOC instructional designers determine the most appropriate social media technology to use as an instructional design strategy to facilitate student achievement of course objectives. This study used a basic qualitative methodology, where six MOOC instructional designers and instructors who designed and developed MOOCs participated in semi-structured interviews via Zoom. The participants were chosen because of their title as either MOOC instructional designers or instructors who had designed and developed their own MOOCs. Findings revealed that the social media platform selections were driven by the platform's relevance to the MOOC content and requiring capabilities to function as collaborative spaces facilitating student to student and instructor to student engagement and communication. The social media platform also required the capability to serve as a para learning environment used in conjunction with the MOOC itself at little to no cost to the student or university that facilitated community building based on common learning goals of like-minded students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]